sole mark

sole mark

[′sōl ‚märk]
(geology)
An irregularity or penetration on the undersurface of a sedimentary stratum.
References in periodicals archive ?
For instance, Karl Barth has commended "apostolicity" as the sole mark of the church.
There were a number of marks that appeared to be in blood and not in blood of possible footwear sole marks in the tiled area," said Mr Bluer.